US2177374A - Electron discharge device - Google Patents

Description

Oct. 24, 1939.

R. ORTHUBER AL ELECTRON DISCHARGE DEVICE 2 Sheets-Sheet 1 Filed March 26, 1937 NTORS ORT HUBER STEUDEL INVE RI RD Oct. 24, 1939. R. ORTHUBER ET AL 2,177,374

ELECTRON DISCHARGE DEVICE Filed March 26, 1937 2 Sheets-Sheet 2 I I IQ I I INVENTORB RlCHARD ORTHUBER EBERHARD STELI DEL ATTORNEY The essential features of this improved photo- Patented Oct 24, 1939 meine Karl- Ufer 2,177,374 ELECTRON DISCHARGE ,nnvIoE Richard Orthuber, Berlin, and Eberhard st'euaei,

'Berlin-Dahlem; Germany, assignors to Allge- Elektricitats-Gesellschaft, Friedrich- Application March 26, 1937, Serial No. 133, 140

In Germany March 31,1936

j 'It is known that two photo-electric currents can-beampli'fied by an electron multiplier in the following manner: The photo-cathode forms one plate "of a plate condenser, the other plate of which is provided with a layer capable of producing s'econdaryelectrons when bombarded'by suificientlyhigh velocityelectrons. To the plates ofthe condenser is applied 'an' alternating voltage so that the electrons liberated at the photo- 'cathode are accelerated between the plates. At every impingement upon one of the two plates of; the-condenser ormultiplier, secondary electrons are liberated which are thus multiplied or increased in" number in this cascade-like man- I her. The thus-amplified photo-current can then be collected bymeans of a cylindrical anode provided'ibetween' the electrodes or plates. An 'essential feature in the arrangement resides in the provision of a 'magnetic'fieldQthe direction of which is the same as the direction of the alternating electrostatic field.

' The employment of this particular method of dynamic electron multiplication necessitates a v comparatively complicated structure and system.

Thepresent improved photo-tube and amplifier does not suffer from these drawbacks, but is, as regards its structure and-it's operation, similar to an ordinary photo-tubeas will appear from the detailed description formingpart of this specification.

tube and electron multiplier are that the photocathodes, the collector anode, the tuning system,

. and the: oscillation generator are housed in a common vacuumvessel.

Such a compact arrangement'of the elements and electrodes mentioned is rendered possible first of all by making use of a frequency of the order or magnitude of 1000' megacycles per secohdpwhereby the possibility is afforded to p give the alternating voltage a comparatively large amplitude. The effects obtained by the large amplitude are first. a greater output of secondary electrons and secondly, because of the high frequency of the alternating voltage and the effect of the'larger amplitude, the electrons need cover only a short distance Within a half-cycle whereby it is possible that the distance between the plates of multiplier electrodes can be small. Another advantage of the employment of t the high frequency, that is to say, of short waves, is that the I tuning can be effected by a short Lecher system provided in the same vacuum vessel. i. The invention may best be described by reierring to the drawings, wherein:

8 Cl'a'ims. (cream-27.5) i

. Figures 2 and 3 represent modifications of the form shown in "Figure 1, and

Figures and-5 represent other forms of photoelectron multipliers.

Referring now to Figure l,an oscillation generator I is coupled with the Lecher wires 3 and 4 by means of the condensers 2. (This oscillation generator is shown only in Figure 1 and is omitted in Figures 2 and 3, and must be supposed to be situated near the righthand endof each of these figures within the vacuum tube.) The oscillator maybe, for instance, a Barkhausen short-wave oscillator or may have any other wiring connections suited for the production of high frequency oscillations. If a particularly great constancy of the amplification is desired, it may be necessary to stabilize the oscillator frequency.

In Figure l thephoto-cathode electrode 5 must be designed asa semi-transparent layer so that the light arriving in the direction I from the window 8 can find access into the multiplier.

Electrodes 5 and 6 arethe'plates of the multi- 1 plier and the secondary electrons producedat the plates -are collected by 'the anode 9. For focusing the electrons a magnetic field is produced-in the coil III which is positioned outside the tube.

In the arrangement shown in Figure 2, the magnetic field is produced by a magnet I I, which, if .desired, may be a permanent magnet. The pole piece of the magnetis provided with an aperture I2 to permit the passage of light on to the photocathode electrode I3. The electrodes I3 and I4 form the plates of the multiplier and electrode I4 is either semi-transparent or is provided with an aperture I5 in order to permit light to reach the electrode I3.

In Figure 3 a more compact arrangement of the members concerned is attained by including the magnet poles I I. within the tube.. The pole pieces at the same time, serve as carriers for the photocathodes or electrodes I3 and I4.

In Figures 4, and 5 the electron multiplier is usedas the oscillation generator. In Figure 4 elements I6 and I1 denote the two cathodes or electrodes of the multiplier across which is connected. a condenser I8 and a self-inductance I9. The anode cylinder 20 can be connected, for instance, with the middle portion of the selfinductance I9, and a source of potential may be included in this connection. In this wiring connection the multiplier excites itself, if the accelerating circuit with .the capacity l8 and Figure 5.

photo-electrons liberated from one of these elec-' trodes. Such an arrangement, which constitutes a photo-tube and an amplifier, is illustrated in The multiplier 22 serves in this case for the generation of oscillationsand the multiplier 23 serves for the amplification. Both multipliers are connected together by means of the mutual inductances 24 and 25, which presents the advantages that the light ariving in the direction 2t canbe used at the same time for the excitation of the oscillation generator 22, in that it is-distributed to both multipliers by, means of a "suitable mirrorii'l, the light being transmitted through passages 28. i i -With,those constructional forms in which per Inanent magnets are arranged withinthe tube,

these magnets can, if desired, be designed as part of the Lecher system. v

. Various modifications maybe made in the invention without departing from the spirit and scope thereof, .and it'is desired that any and all such modifications shall be considered within the purview of the invention, except as limited by the hereinafterappended claims.

We claim: 1 1. An electron discharge device comprisingan J envelope, a sourceof oscillationswithin the ,en-

'velope of the Barkhausen type comprising an electron emitter, a grid element'and' an anode, a Lecher-system comprising a pair of conductors,

means couplingthe conductors to said grid and anode, a pair of electronemissive surfaces in the envelope one of which is light responsive; means connecting said surfaces to saidconductors, a

collector anode adjacent said surfaces, and means to produce a magnetic field in the region of said surfaces. i r

2. An electron discharge device comprising an envelope, means in the envelope adapted to produce oscillations comprising an electron emitter, a grid electrode and an anode, a Lecher tuning system comprising a pair of parallel conduictoirsi; means coupling said conductors to'said gridand r anode, a pair ofsurfaces having'high secondary electron emission qualities in the envelope, one

of said surfaces beinglight responsive, means positioning said surfaces insubstantially parallel relation and connecting said surfaces to said conductors, .a collector anode for said surfaces, and means to produce a magnetic field substantially normal to said surfaces. r

., 3. An electron discharge device .comprisingan envelope, means inthe envelope adapted to pro-l an electron emitter,

duce oscillations comprising a grid electrodeiand an anode, a tuning system comprising a pair of parallel conductors, means coupling said conductors to said grid and anode,"

a pair of surfaces having high=secondary elec tronemission qualities in the envelope, means positioning said surfaces insubstantially parallelrelation and connecting said surfaces to said con;

ductorsfa collector anode for said surfaces, and

means to produce a magnetic field substantially normal to said surfaces, said last named means being located Within the envelope.

' 4, An electron discharge device comprising'an envelope, means in the envelope to produce oscillations comprising an electron emitter, a grid electrode and an anode, a tuning system comprising a pair of parallel conductors, means cou- H pling said conductors to said grid and anode, a;

pair of surfaces having high secondary electron emission qualities in the envelope, means positioning said surfaces in substantially parallelrelation and connecting said surfaces to said conductors, a collector anode for said surfaces and means to produce a 'magnetic field substantially normal to said surfaces, saidlast named means.

being located within the envelope and forming at least a part of the tuning system.

5. An electron discharge device comprising an envelope, means within the envelope to produce oscillations, a pair of parallel conductors inthe' envelope forming a Lecher tuning system, means connecting said conductorsto the sourceof oscil-" lations, a pair of surfaces having a secondary elec-' tron emission ratiogreater thanjone, one of said surfaces'being lightresponsive, a collector anode for said surfaces, means positioning saidsurfaces in substantially parallelrelation and connecting said surfaces tosaid conductors, and means to v produce a magneticfield substantially normal to" said surfacesu i a i 6. An electron Jdis'charge devicecomprising an envelope'means within the envelope to produce oscillations,-, apair of parallelconductors in the envelope forming a tuning system, means connecting saidconductors to the source of oscillations, a pair of surfaces having, a secondary electron emission ratio greater than one, a collector anode for "said surfaces, means positioning said surfaces in substantially parallel relation and connecting said surfaces tosaid 'conductors,and means to producea magnetic field substantially normal tosaid surfaces, said last named means including magnetic pole pieces one of which is provided with an opening extending in the direction of one ofithe surfaces. I

7. An electron discharge device comprising an envelope, means in the envelope to produce oscillations, a pair of magnetic members in the en- 7 velope, means connecting said members to the source of oscillations and positioning the 'pole faces of the member in substantially parallel relationship, means on each poleface for producing secondary electronsunder electron bombardment,"

one of said means being light responsive, and' a collector anode for. said means. j W

8. An electron discharge :device comprising an envelope, means in the envelope to produce oscillations, apair of parallel magnetic members in the envelope, means connecting said members to the source of oscillations and positioning the pole faces of the member in substantially parallel relationship,'means on each pole face for producing secondary electrons under electron bombardment, and a collector anodefor, said means, one of said,

last named means being light responsive and. one

of said .pole faces being provided withv an opening extending in the directionof theother pole face.

RICHARD ORTHUBER.

EBERHARD STEUDEL.

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